Check unwinding recursive calls.
Verify we can unwind in absence of unwind tables.
PiperOrigin-RevId: 513506498
Change-Id: Ib87240b7481dae3a4513c944e17a7924a54926e9
This change should make it less confusing where utility code comes from.
Having it in two places made sense when we were debating whether to publish
Sandbox2 separately, but not any longer.
Follow-up changes will move `sandbox2/util.h` and rename the remaining
`sandbox2/util` folder.
PiperOrigin-RevId: 351601640
Change-Id: I6256845261f610e590c25e2c59851cc51da2d778
